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Association of Major Food Sources of Fructose-Containing Sugars With Incident Metabolic Syndrome: A Systematic Review and Meta-analysis.
Semnani-Azad, Z, Khan, TA, Blanco Mejia, S, de Souza, RJ, Leiter, LA, Kendall, CWC, Hanley, AJ, Sievenpiper, JL
JAMA network open. 2020;3(7):e209993
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Fructose is a type of sugar that has been implicated as a contributor to the development of metabolic syndrome (MetS), which is a condition where large waist circumference, high blood pressure and elevated blood lipid levels may all coexist. However, it remains unclear as to the role of fructose containing foods in the development of MetS. This systematic review and meta-analysis of 13 prospective cohort studies aimed to determine the association of several fructose containing foods and drinks with MetS. The results showed that sugary drinks containing fructose increased the risk of MetS, whereas no associations were found with mixed fruit juice, 100% fruit juice, honey, ice cream or confectionary. Interestingly fruit and yoghurt containing fructose decreased the risk of developing MetS. It was concluded that fructose containing food and drinks are not all equal in their biological effects. Sugary drinks increased the risk of developing MetS but yoghurt and fruit had a protective effect against development. Reasons for this could be due to a generally unhealthier lifestyle in those who consume sugary drinks or may be due to the increased protective effects associated with the vitamins and minerals in fruit and yoghurt. This study could be used by healthcare professionals to recommend a diet eliminating sugary drinks and containing regular fruit and yoghurt intake.
Abstract
Importance: Sugar-sweetened beverages (SSBs) are associated with increased risk of metabolic syndrome (MetS). However, the role of other important food sources of fructose-containing sugars in the development of MetS remains unclear. Objective: To examine the association of major food sources of fructose-containing sugars with incident MetS. Data Sources: MEDLINE, Embase, and Cochrane Library were searched from database inception to March 24, 2020, in addition to manual searches of reference lists from included studies using the following search terms: sugar-sweetened beverages, fruit drink, yogurt, metabolic syndrome, and prospective study. Study Selection: Inclusion criteria included prospective cohort studies of 1 year or longer that investigated the association of important food sources of fructose-containing sugars with incident MetS in participants free of MetS at the start of the study. Data Extraction and Synthesis: Study quality was assessed using the Newcastle-Ottawa Scale. Extreme quantile risk estimates for each food source with MetS incidence were pooled using a random-effects meta-analysis. Interstudy heterogeneity was assessed (Cochran Q statistic) and quantified (I2 statistic). Dose-response analyses were performed using a 1-stage linear mixed-effects model. The certainty of the evidence was assessed using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Results were reported according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Main Outcomes and Measures: Pooled risk ratio (RR) of incident MetS (pairwise and dose response). Results: Thirteen prospective cohort studies (49 591 participants [median age, 51 years; range, 6-90 years]; 14 205 with MetS) that assessed 8 fructose-containing foods and MetS were included. An adverse linear dose-response association for SSBs (RR for 355 mL/d, 1.14; 95% CI, 1.05-1.23) and an L-shaped protective dose-response association for yogurt (RR for 85 g/d, 0.66; 95% CI, 0.58-0.76) and fruit (RR for 80 g/d, 0.82; 95% CI, 0.78-0.86) was found. Fruit juices (mixed and 100%) had a U-shaped dose-response association with protection at moderate doses (mixed fruit juice: RR for 125 mL/d, 0.58; 95% CI, 0.42-0.79; 100% fruit juice: RR for 125 mL/d, 0.77; 95% CI, 0.61-0.97). Honey, ice cream, and confectionary had no association with MetS incidence. The certainty of the evidence was moderate for SSBs, yogurt, fruit, mixed fruit juice, and 100% fruit juice and very low for all other food sources. Conclusions and Relevance: The findings of this meta-analysis suggest that the adverse association of SSBs with MetS does not extend to other food sources of fructose-containing sugars, with a protective association for yogurt and fruit throughout the dose range and for 100% fruit juice and mixed fruit juices at moderate doses. Therefore, current policies and guidelines on the need to limit sources of free sugars may need to be reexamined.
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Prevention of Type 2 Diabetes by Lifestyle Changes: A Systematic Review and Meta-Analysis.
Uusitupa, M, Khan, TA, Viguiliouk, E, Kahleova, H, Rivellese, AA, Hermansen, K, Pfeiffer, A, Thanopoulou, A, Salas-Salvadó, J, Schwab, U, et al
Nutrients. 2019;11(11)
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With Type 2 Diabetes growing globally this paper analyses whether T2D is preventable with lifestyle measures including diet. Seven RCTs were included for review with a total of 4090 participants, and 2466 incidents of T2D, and were chosen on the basis that the lifestyle interventions included both physical exercise and diet (typically Mediterranean Diet). They found that diet and lifestyle intervention reduced the risk of T2D by 47%. Sustained risk reduction was also found in follow-up studies up to 10 years later with participants maintaining improved blood glucose control. Lifestyle interventions may also reduce risk factors for cardiovascular disease. Weight reduction was considered a cornerstone of preventing T2D and adherence to lifestyle changes a key element in long term prevention. Dietary foods reviewed include processed meats, white rice and sugars which correlated highly with T2D whilst leafy greens, berries, wholegrains, legumes, dietary fibre and yoghurt correlate with a lower risk of T2D. Dietary patterns of skipping breakfast and snacking correlate higher with T2D. Different criteria for evaluating physical activity estimate that it reduces risk factors by 50%. In conclusion there is high evidence that lifestyle factors which optimise diet, increase physical activity and promote weight reduction are preventative factors for T2D and can be sustained long term.
Abstract
Prevention of type 2 diabetes (T2D) is a great challenge worldwide. The aim of this evidence synthesis was to summarize the available evidence in order to update the European Association for the Study of Diabetes (EASD) clinical practice guidelines for nutrition therapy. We conducted a systematic review and, where appropriate, meta-analyses of randomized controlled trials (RCTs) carried out in people with impaired glucose tolerance (IGT) (six studies) or dysmetabolism (one study) to answer the following questions: What is the evidence that T2D is preventable by lifestyle changes? What is the optimal diet (with a particular focus on diet quality) for prevention, and does the prevention of T2D result in a lower risk of late complications of T2D? The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was applied to assess the certainty of the trial evidence. Altogether seven RCTs (N = 4090) fulfilled the eligibility criteria and were included in the meta-analysis. The diagnosis of incident diabetes was based on an oral glucose tolerance test (OGTT). The overall risk reduction of T2D by the lifestyle interventions was 0.53 (95% CI 0.41; 0.67). Most of the trials aimed to reduce weight, increase physical activity, and apply a diet relatively low in saturated fat and high in fiber. The PREDIMED trial that did not meet eligibility criteria for inclusion in the meta-analysis was used in the final assessment of diet quality. We conclude that T2D is preventable by changing lifestyle and the risk reduction is sustained for many years after the active intervention (high certainty of evidence). Healthy dietary changes based on the current recommendations and the Mediterranean dietary pattern can be recommended for the long-term prevention of diabetes. There is limited or insufficient data to show that prevention of T2D by lifestyle changes results in a lower risk of cardiovascular and microvascular complications.
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Positioning the Value of Dietary Carbohydrate, Carbohydrate Quality, Glycemic Index, and GI Labelling to the Canadian Consumer for Improving Dietary Patterns.
Marinangeli, CPF, Castellano, J, Torrance, P, Lewis, J, Gall Casey, C, Tanuta, J, Curran, J, Harding, SV, Jenkins, DJA, Sievenpiper, JL
Nutrients. 2019;11(2)
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Nutrition science dictates that carbohydrates are elements of a healthy diet. However, consumers have increasingly antagonistic feelings toward dietary carbohydrate as a cause of weight gain. The aim of this study was to understand Canadian consumers’ knowledge and perception of dietary carbohydrates, carbohydrate quality, and the glycaemic index. A secondary aim was to identify a strategy for positioning the glycaemic index as a consumer-facing labelling program. The study conducted focus groups with forty-seven individuals. The participants were recruited into three consumer segments (normal body weight, previously obese and overweight/obese). Results demonstrate that the focus groups interpreted ‘carbohydrate quality’ as the categorization of carbohydrate foods as either ‘good’ or ‘bad’. Additionally, Canadians were receptive to a labelling program that identifies carbohydrate food as having low glycaemic index. However, since low glycaemic index was perceived as a tool for diabetes management, low glycaemic labelling requires significant consumer education and adoption by industry. Authors conclude that glycaemic index could be used as a consumer-facing labelling program for Canadians and assist with de-stigmatizing carbohydrate foods.
Abstract
The objectives of this qualitative study was to: (1) understand Canadian consumers' knowledge and perception of dietary carbohydrates, carbohydrate quality, and the glycemic index (GI); and (2) determine Canadian's receptiveness to GI labelling to assist with identifying and consuming foods of higher carbohydrate quality. Focus groups were recruited in Vancouver, Toronto, and Montreal and grouped according to body mass index (BMI) (NBW, normal body weight; PO, previously obese; and OW/OB, overweight/obese) and diagnosis with prediabetes and diabetes (PO (Vancouver) and OW/OB (Montreal and Toronto). Subjects in all groups linked excess consumption of carbohydrate with weight gain. PO and OW/OB groups were conflicted between perceived negative consequences and feelings of pleasure associated with carbohydrate consumption. Subjects were largely unfamiliar with the term 'carbohydrate quality', but were often associated with classifying carbohydrates as 'good' or 'bad'. The concept of the GI resonated well across groups after exposure to corresponding educational materials. However, NBW groups largely felt that the GI was irrelevant to their dietary choices as they did not have a history of diabetes. PO and OW/OB groups associated the GI with diabetes management. The concept of a GI labelling program to help facilitate healthier carbohydrate choices was well received across all groups, especially when the low GI was interpreted as giving permission to consume foods they enjoyed eating. Results suggest that the GI could be used as a consumer-facing labelling program in Canada and assist with de-stigmatizing carbohydrate foods by helping to facilitate the consumption of carbohydrate foods that align with healthy dietary patterns.
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Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations.
Livesey, G, Taylor, R, Livesey, HF, Buyken, AE, Jenkins, DJA, Augustin, LSA, Sievenpiper, JL, Barclay, AW, Liu, S, Wolever, TMS, et al
Nutrients. 2019;11(6)
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It is generally accepted that certain diet and lifestyle choices contribute to a person’s risk of developing type 2 diabetes (T2D). In this meta-analysis, researchers set out to review previous studies and assess whether there is any evidence that the amount and type of carbohydrate (measured by Glycaemic Index (GI) and Glycaemic Load (GL)) in a person’s diet has a direct influence on their risk of developing T2D. The authors concluded with a high level of confidence that eating high GI and GL foods can lead to a higher risk of developing T2D. They suggest that nutrition advice that favours low GI and GL foods could produce significant cost savings for public healthcare.
Abstract
While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.
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Food sources of fructose-containing sugars and glycaemic control: systematic review and meta-analysis of controlled intervention studies.
Choo, VL, Viguiliouk, E, Blanco Mejia, S, Cozma, AI, Khan, TA, Ha, V, Wolever, TMS, Leiter, LA, Vuksan, V, Kendall, CWC, et al
BMJ (Clinical research ed.). 2018;363:k4644
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With increasing evidence linking fructose to metabolic disease, current dietary guidelines recommend a reduction of added free sugars, especially fructose-containing sugars from sugars-sweetened beverages (SSBs). However, it is currently unclear whether the negative impact of fructose on metabolic health is as implicative in the context of an overall dietary consumption pattern. The aim of this study was to assess the effect of different sources of fructose-containing sugars on glycaemic control in people with and without diabetes. This review analysed 155 controlled intervention studies and found that fructose-containing sugars in the form of fruit do not have a harmful effect on glycaemic control when compared to energy-matched macronutrient substitutions. Further, harmful effects on glycaemic control were found when excess energy in the form of fructose-containing sugars from SSBs were added to the diet. The authors conclude the food source of fructose-containing sugars on glycemic control is important in the conversation of metabolic health and glycaemic control. While further research is needed to assess a wider variety of food sources, public health professionals should consider the influence of food sources when developing dietary recommendations for the prevention and management of diabetes and other metabolic conditions.
Abstract
OBJECTIVE To assess the effect of different food sources of fructose-containing sugars on glycaemic control at different levels of energy control. DESIGN Systematic review and meta-analysis of controlled intervention studies. DATA SOURCES Medine, Embase, and the Cochrane Library up to 25 April 2018. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Controlled intervention studies of at least seven days' duration and assessing the effect of different food sources of fructose-containing sugars on glycaemic control in people with and without diabetes were included. Four study designs were prespecified on the basis of energy control: substitution studies (sugars in energy matched comparisons with other macronutrients), addition studies (excess energy from sugars added to diets), subtraction studies (energy from sugars subtracted from diets), and ad libitum studies (sugars freely replaced by other macronutrients without control for energy). Outcomes were glycated haemoglobin (HbA1c), fasting blood glucose, and fasting blood glucose insulin. DATA EXTRACTION AND SYNTHESIS Four independent reviewers extracted relevant data and assessed risk of bias. Data were pooled by random effects models and overall certainty of the evidence assessed by the GRADE approach (grading of recommendations assessment, development, and evaluation). RESULTS 155 study comparisons (n=5086) were included. Total fructose-containing sugars had no harmful effect on any outcome in substitution or subtraction studies, with a decrease seen in HbA1c in substitution studies (mean difference -0.22% (95% confidence interval to -0.35% to -0.08%), -25.9 mmol/mol (-27.3 to -24.4)), but a harmful effect was seen on fasting insulin in addition studies (4.68 pmol/L (1.40 to 7.96)) and ad libitum studies (7.24 pmol/L (0.47 to 14.00)). There was interaction by food source, with specific food sources showing beneficial effects (fruit and fruit juice) or harmful effects (sweetened milk and mixed sources) in substitution studies and harmful effects (sugars-sweetened beverages and fruit juice) in addition studies on at least one outcome. Most of the evidence was low quality. CONCLUSIONS Energy control and food source appear to mediate the effect of fructose-containing sugars on glycaemic control. Although most food sources of these sugars (especially fruit) do not have a harmful effect in energy matched substitutions with other macronutrients, several food sources of fructose-containing sugars (especially sugars-sweetened beverages) adding excess energy to diets have harmful effects. However, certainty in these estimates is low, and more high quality randomised controlled trials are needed. STUDY REGISTRATION Clinicaltrials.gov (NCT02716870).
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Effect of dried fruit on postprandial glycemia: a randomized acute-feeding trial.
Viguiliouk, E, Jenkins, AL, Blanco Mejia, S, Sievenpiper, JL, Kendall, CWC
Nutrition & diabetes. 2018;8(1):59
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Dried fruits show promising potential for blood glucose management. However, the effect of combining dried fruits with high glycaemic index (GI) foods has not been adequately addressed. The main objectives of this study were to: a) quantify the GI of 4 different types of dried fruit (dates, apricots, raisins, sultanas); and b) assess the ability of these 4 dried fruits to decrease the postprandial glycaemic response to white bread by partially displacing available carbohydrate and by providing a ‘catalytic’ dose of fructose. This study is a randomised multiple - crossover acute feeding trial which enrolled 10 participants of which 7 were males. Each participant underwent a total of 15 separate study meals consisting of 3 white bread control meals and 12 dried fruit test meals. Results demonstrate that dried fruit have a lower GI than white bread and can lower the glycaemic response of white bread through displacement of half of the available carbohydrate. None of the dried fruits showed a beneficial ‘catalytic’ fructose effect. Authors conclude that their findings may help to stimulate important industry innovation and improve the design of future clinical investigations that will potentially lead to the use of dried fruits as an effective tool to modify the glycaemic response of high carbohydrate foods.
Abstract
BACKGROUND/OBJECTIVES To investigate the effect of dried fruit in modifying postprandial glycemia, we assessed the ability of 4 dried fruits (dates, apricots, raisins, sultanas) to decrease postprandial glycemia through three mechanisms: a glycemic index (GI) effect, displacement effect, or 'catalytic' fructose effect. SUBJECTS/METHODS We conducted an acute randomized, multiple-crossover trial in an outpatient setting in 10 healthy adults. Participants received 3 white bread control meals and 12 dried fruit test meals in random order. The test meals included each of 4 dried fruits (dates, apricots, raisins, sultanas) alone (GI effect), 4 of the dried fruits displacing half the available carbohydrate in white bread (displacement effect), or 4 of the dried fruits providing a small 'catalytic' dose (7.5 g) of fructose added to white bread ('catalytic' fructose effect). The protocol followed the ISO method for the determination of GI (ISO 26642:2010). The primary outcome was mean ± SEM GI (glucose scale) for ease of comparison across the three mechanisms. RESULTS Ten healthy participants (7 men, 3 women; mean ± SD age and BMI: 39 ± 12 years and 25 ± 2 kg/m2) were recruited and completed the trial. All dried fruit had a GI below that of white bread (GI = 71); however, only dried apricots (GI = 42 ± 5), raisins (GI = 55 ± 5), and sultanas (51 ± 4) showed a significant GI effect (P < 0.05). When displacing half the available carbohydrate in white bread, all dried fruit lowered the GI; however, only dried apricots (GI = 57 ± 5) showed a significant displacement effect (P = 0.025). None of the dried fruits showed a beneficial 'catalytic' fructose effect. CONCLUSIONS In conclusion, dried fruits have a lower GI and reduce the glycemic response of white bread through displacement of half of the available carbohydrate. Longer-term randomized trials are needed to confirm whether dried fruit can contribute to sustainable improvements in glycemic control. TRIAL REGISTRATION ClinicalTrials.gov identifier, NCT02960373.
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Relation of total sugars, fructose and sucrose with incident type 2 diabetes: a systematic review and meta-analysis of prospective cohort studies.
Tsilas, CS, de Souza, RJ, Mejia, SB, Mirrahimi, A, Cozma, AI, Jayalath, VH, Ha, V, Tawfik, R, Di Buono, M, Jenkins, AL, et al
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. 2017;189(20):E711-E720
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Sugars, particularly fructose-containing sugars, have been implicated as an important driver in the rise in incidence of type 2 diabetes. The aim of this study was to determine the role of fructose-containing sugars independent of food form in the development of type 2 diabetes. This study is a systemic review and meta-analysis of prospective cohort studies. The study included 15 cohorts from 9 studies. Results indicate that intakes of total sugars and fructose were not associated with type 2 diabetes, whereas intake of sucrose was associated with an 11% decrease in type 2 diabetes. Authors conclude that in the absence of a clear signal for harm, sugars alone do not appear to explain the relation between sugar-sweetened beverages and type 2 diabetes.
Abstract
BACKGROUND Sugar-sweetened beverages are associated with type 2 diabetes. To assess whether this association holds for the fructose-containing sugars they contain, we conducted a systematic review and meta-analysis of prospective cohort studies. METHODS We searched MEDLINE, Embase, CINAHL and the Cochrane Library (through June 2016). We included prospective cohort studies that assessed the relation of fructose-containing sugars with incident type 2 diabetes. Two independent reviewers extracted relevant data and assessed risk of bias. We pooled risk ratios (RRs) using random effects meta-analyses. The overall quality of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. RESULTS Fiffeen prospective cohort studies (251 261 unique participants, 16 416 cases) met the eligibility criteria, comparing the highest intake (median 137, 35.2 and 78 g/d) with the lowest intake (median 65, 9.7 and 25.8 g/d) of total sugars, fructose and sucrose, respectively. Although there was no association of total sugars (RR 0.91, 95% confidence interval [CI] 0.76-1.09) or fructose (RR 1.04, 95% CI 0.84-1.29) with type 2 diabetes, sucrose was associated with a decreased risk of type 2 diabetes (RR 0.89, 95% CI 0.80-0.98). Our confidence in the estimates was limited by evidence of serious inconsistency between studies for total sugars and fructose, and serious imprecision in the pooled estimates for all 3 sugar categories. INTERPRETATION Current evidence does not allow us to conclude that fructose-containing sugars independent of food form are associated with increased risk of type 2 diabetes. Further research is likely to affect our estimates. TRIAL REGISTRATION ClinicalTrials.gov, no. NCT01608620.